Rudd
Rudd are an invasive European minnow-family fish that arrived in Ontario's lower Great Lakes system in 1990, likely carried in through the live-bait trade. They've since spread through the St. Lawrence River and parts of Lakes Ontario and Erie.
They're not a target species — they're a management concern — but anglers encounter them regularly in weedy, slow-water areas and should know how to identify and report them.
Scientific Name: Scardinius erythrophthalmus
Also known as Pearl Roach, Redeye
- Deep, compressed body with brassy yellow-gold sides, a dark greenish-brown back, and a whitish belly fully covered in scales — including a scaled keel along the belly between the pelvic and anal fins.
- Pectoral, pelvic, and anal fins are bright reddish-orange; dorsal and tail fins are reddish-brown. The fin color is the fastest field ID: much redder than a Golden Shiner's yellowish fins.
- Small upturned mouth with a distinctly protruding lower lip — angled for surface feeding. Eyes are red or gold with a red spot, unlike the yellow-green eyes of the Golden Shiner.
- Typical fish run 15–25 cm; larger individuals can reach 50 cm, though most encountered in Ontario waters are on the smaller end of that range.
What to know
Habitat Distribution
- Introduced, not native — first confirmed in Canada in 1990 in the St. Lawrence River in Ontario. Now present in scattered locations along the St. Lawrence and in western Lake Ontario and eastern Lake Erie.
- Has not been confirmed in any inland Ontario lake to date; distribution remains tied to the lower Great Lakes corridor and the St. Lawrence system.
- Prefers calm, slow-moving or still water with dense aquatic vegetation — ponds, weedy lake bays, and sluggish river backwaters.
- Tolerates a wide range of freshwater conditions including poor water quality, which helps it establish in degraded nearshore habitat.
Key Locations
- St. Lawrence River (Ontario section) — first confirmed Canadian location in 1990; scattered populations persist along this corridor.
- Western Lake Ontario — rudd were confirmed here in 1997 and remain present in nearshore weedy areas.
- Eastern Lake Erie — confirmed in 1997 alongside the Lake Ontario discovery; slow-water nearshore habitat along this stretch holds fish.
Specific Spots
- Dense weed beds and submerged vegetation along shorelines — rudd feed heavily on aquatic plants and the invertebrates living among them, so thick vegetation is the first place to look.
- Calm backwaters and sheltered bays where current is minimal; they avoid fast-moving water and congregate where flow slackens.
- Near the surface in warm, still conditions — their upturned mouth is built for surface and near-surface feeding, and they'll visibly dimple the water when active.
Rudd FAQ
Answers from onWater's species guide.
What are the best lures and bait for Rudd?
Bread flake, dough balls, and soft plant-based baits fished under a small float, these match the rudd's plant-grazing diet and are the most consistent producers in European fisheries where rudd are deliberately targeted.
What flies work for Rudd?
Small dry flies, Elk Hair Caddis or parachute-style patterns imitating surface insects, work when rudd are visibly dimpling near weed edges.
When is the best time to fish for Rudd?
Late spring through summer (roughly May–September) is when rudd are most active in Ontario's lower Great Lakes waters, as temperatures climb into their preferred 10–22°C range. Surface feeding activity peaks on calm summer mornings and evenings when fish are visibly working the weed edges.
How do you catch Rudd?
Rudd are not deliberately targeted by most Canadian anglers, but those who do fish for them use light float rigs with bread or small baits along weedy shorelines in calm water. Early morning, when fish are visibly feeding at the surface, is the most productive window.
What do Rudd eat?
Adults eat aquatic plants and insects, both surface and subsurface. Small hooks baited with bread, dough, or soft plant-based baits work on the same feeding behavior that makes them graze vegetation. A small dry fly or surface nymph can also draw strikes when they're feeding at the top.
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